Nightrider350

After running the car for 30 minutes to break in the cam, I took it for a little test drive around the parking lot. After my second pass, I gave it about half throttle, and it started banging real loud. I took off the valve covers and discovered one of the nuts on my CompCams roller rockers has unscrewed completely, thus not allowing the exhaust valve to move. Earlier that day, we had torqued them down to where we could barely move the pushrod, then torqued them an extra half-turn. Once done, we tightened the allen screw on the inside of the nut. It's supposed to lock the nut in place, but apparently it didn't work. We thought we did what the directions said, but is there any special way to install these types of rockers? Could another problem be that the pushrods are a little too long?

RB83L69

It's basically impossible to tighten the set screw tight enough, by itself. The answer is not to try to crank down on the Allen screw.

Tighten the set screw up as tight as you can conveniently get it with your Allen wrench, without any effort that comes close to stripping the hex or anything remotely like that; then tighten the main nut and the Allen together, with both a 5/8" box wrench and an Allen. You'll find that you can get them ALOT tighter that way, without really stressing the tools or the hardware at all.

Nightrider350

I'm supposed to tighten the allen set screw inside the nut prior to tightening the nut on the rocker? I thought they were supposed to stay untightened and loose until the nut was snug.

ede

lot of people think that and then have problems with rocker nuts backing off

RB83L69

I know what the instructions say. To put it plainly, they don't work.

One at a time, loosen the set screws, adjust the valves to zero lash, and tighten the set screws gently. Turn the motor off. One at a time, loosen the set screw, add a little less your desired lifter preload setting (which one half turn on the nut probably, so add 3/8 turn or so), re-tighten the set screw gently, then put your box-end wrench on the nut and the Allen wrench in the set screw at the same time, and tighten the dog poop out of it, by moving the nut and the set screw at the same time. They will then stay put.

Damon

Do what RB said. You'll never have another problem with them backing off again. All us "old heads" have been doing it this way for years. Like RB said, the instructions are wrong and have been for decades.